At this point you might be asking yourself: why are fish eating plastic instead of, well, whatever it is they're supposed to eat? And new research, released this week in Proceedings B, offers an answer: in seawater, plastic smells like food.

Researchers from the University of California, Davis, and San Francisco's Aquarium of the Bay, used anchovies—a fish known to eat plastic—for their study. They gave the wild-caught fish access to two types of plastic—one that has been submerged in seawater for three weeks, and "clean" plastic that had not been exposed to water—and tested the anchovies' reactions. The researchers found that the plastic exposed to seawater "stimulated a behavioral response consistent with foraging in captive anchovy schools." In other words, the anchovies thought that plastic smelled tasty.

"This is the first behavioral evidence that plastic debris may be chemically attractive to marine consumers," the researchers wrote. "These chemical cues may lure [fish], such as anchovy, into regions of high plastic density and activate foraging behaviors, thus making it difficult to ignore or reject plastic items as potential prey. It is therefore not surprising that [these fish] are frequent consumers of plastic debris."

What's more, the researchers found that plastic which has been submerged in seawater begins to resemble food, which gives fish misleading visual cues that it's safe to eat.

The researchers didn't offer any solutions to encourage fish to stop eating the plastic that's already in our oceans. But they did note this is a big problem—and not just for sea creatures. "Humans are at the top of these food chains; therefore, results of such future studies may have important consequences for human health."